Pallets are customarily used to transport and store goods. A pallet typically includes an upper deck and a lower deck separated by support blocks. Pallets have traditionally been formed of wood. While advantageous in terms of cost, wood pallets have many disadvantages. For example, they are subject to breakage and are therefore reusable only over a short period of time. Wooden pallets are also difficult to maintain in a sanitary condition, thereby limiting their usability in applications where sanitation is important, such as in food handling applications.
With the growth of the plastics industry a wide variety of plastics have been investigated to determine their suitability for use in producing pallets. Plastic pallets can easily be molded and are stronger and lighter weight than wooden pallets. They can also be made with recyclable materials. Furthermore, plastic pallets are more durable than wooden pallets.
To increase the durability of plastic pallets, reinforcing elements or rods have been used. For example, U.S. Pat. No. 6,199,488 discloses a reinforced plastic pallet comprising an upper deck formed of a plastic material having a first coefficient of thermal expansion, and a lower deck formed of a plastic material having substantially the first coefficient of thermal expansion. The lower deck includes a plurality of channels formed in its upper surface, and a plurality of reinforcing elements having a second coefficient of thermal expansion different from the first degree of expansion are in the plurality of channels. The channels are provided with retainers to retain the reinforcing elements therein.
U.S. Pat. No. 5,868,080 discloses a reinforced plastic pallet with reinforcing rods. At least some of the reinforcing rods have an exposed surface at a top surface of the pallet. In addition to functioning as a reinforcing member, the exposed surfaces of the reinforcing rods comprise an anti-skid surface for maintaining positioning of a payload on the pallet.
Yet another approach to increase the durability of plastic pallets is disclosed in U.S. Pat. No. 4,735,154. The '154 patent provides a reinforced loading pallet comprising two essentially rectangular matching panels one superposed over the other, with each panel having a rigid frame including ties equipped with hollow, polygonal feet arranged at four outer corners of the frame. At least some of the ties in at least one of the frames are provided with channels, with at least some of the channels intersecting in a single plane. Rods are inserted into the channels for reinforcing the pallet.
While plastic pallets offer several advantages over wood pallets, there is still a demand to increase durability and strength of plastic pallets.